Research is directed at the elucidation of metabolic interrelationships in the membrane phospholipids. Of particular interest are the inositol lipids and phosphatidic acid, since they are particularly responsive to cholinergic agents. We are also interested in acyl dihydroxyacetone phosphate, a lipid precursor in a novel pathway for the formation of lipids. It has special significance in tissues low in glycerophosphate dehydrogenase, including brain and most tumor cells.